Definition from Wiktionary, the free dictionary
|simpl. and trad.|
Literally: in a melon patch or under a plum tree
瓜田李下 (traditional and simplified, Pinyin)
- a position that invites suspicion; liable to lay oneself open to suspicion; be found in a suspicious position; in suspicious circumstances or surroundings
Originates from a longer phrase 瓜田不納履、李下不正冠. It can be compared to the English-language idiom, "caught with one's hand in the cookie jar."